CMOS Detecting Wrong Hard Drive Size After Power Outage

I have two systems with the exact same hardware and both running Windows XP SP2.  They both had a WD 400 hard dirves.  We had a power outage and when they came back on, both of these systems would not boot.  I then noticed that CMOS was showing them as something like 8.4GB.  It was showing the correct drive model, but the wrong size.  I put them in another system and the same thing occurred.  What could cause this?  If the partition table got wiped out, would CMOS report the wrong size.  Is the drive size stored on the drive and possibly that information got wiped out?  Is there anyway to correct the problem?  I was hoping to recover data off the drives if at all possible.   However, with CMOS reporting the wrong disk geometry, I can't even use a RAW recovery.  Any ideas or suggestions would be appreciated.